Scientists have just announced a series of discoveries that are considered the “strongest evidence” for the possibility of extraterrestrial life, opening a new chapter in the field of astronomy and astrobiology.
1. Biogas on planet K2-18b
In 2025, a research team using the James Webb Space Telescope (JWST) discovered traces of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the atmosphere of planet K2-18b, 124 light years from Earth. These are compounds that on Earth are only produced by life, such as marine phytoplankton.
K2-18b is classified as a Hycean world - an ocean planet with a hydrogen-rich atmosphere, located in the "habitable zone" of its host star, where liquid water is likely to exist.
Notably, the DMS/DMDS detection level has a scientific confidence level of about 3σ (~99.7%), which is a thousand times higher than that of Earth, making the biological origin hypothesis reasonable. However, scientists remain cautious, emphasizing that more observations are needed to rule out the possibility that these compounds were formed by non-biological processes.
2. “Building blocks of life” from asteroid Bennu
In the Solar System, NASA has also just announced the results from the asteroid Bennu sample brought back by the OSIRIS-REx mission. The analysis showed the presence of amino acids, nitrogen-containing compounds, sodium minerals, and even traces of the primitive “genetic code”.
This finding reinforces the panspermia hypothesis – the idea that life on Earth may have originated from organic components brought by asteroids or comets.
3. Potential for icy moons
The two moons Enceladus (Saturn) and Europa (Jupiter) have long been considered “strong candidates” for life. Data from the Cassini spacecraft has shown that Enceladus erupts with plumes of organic-rich water vapor from its subglacial ocean.
NASA now has high hopes for the Europa Clipper mission, scheduled to arrive at Europa in 2030, to directly search for biological signs in the ice and deep ocean below.
4. Controversial traces
Previously, the meteorite ALH84001 from Mars caused a stir when it was said to contain microscopic structures similar to fossilized bacteria. But so far, this hypothesis has not reached a consensus in the scientific community and is often considered weak evidence.
Location/Source High Evidence Convincing Leve lK2-18bDMS/DMDS Detection – Biogas Strongest to Date Bennu Amino acids, nitrogen, organic compounds Possible origin of extraterrestrial life Enceladus/Europa Liquid water + organic compounds High potential, awaiting exploration missionALH84001 (Mars)Microbial-like microstructure Controversial, lack of solid evidence
The discovery of biogas on planet K2-18b is currently considered the strongest evidence for the possibility of extraterrestrial life. However, the scientific community emphasizes that more data is needed before a firm assertion can be made.
Meanwhile, samples from Bennu and missions to Enceladus and Europa will continue to be important milestones, bringing humanity closer to answering the eternal question: Are we alone in the universe?
Source: AP News
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